Integrating relay and signal mechanisms



Feb. 28, 1956 1.. BODDY INTEGRATING RELAY AND SIGNAL MECHANISMS 3 Sheets-Sheet 1 Filed June 10, 1955 INVENTOR. 16207247! 500 0 77.

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waiupfwgv Feb. 28, 1956 1.. BODDY INTEGRATING RELAY AND SIGNAL MECHANISMS Filed June 10, 1955 3 Sheets-Sheet 2 Feb. 28, 1956 L. BODDY INTEGRATING RELAY AND SIGNAL MECHANISMS 3 Sheets-Sheet 3 Filed June 10, 1955 Gig L INVENTOR.

BY (2/ flm EM ,9 afilgz/st NNN United States Patent INTEGRATING RELAY AND SIGNAL MECHANISMS Leonard Buddy, Ann Arbor, Mich., assignor to King- Seeley Corporation, Ann Arbor, Mich., a corporation of Michigan Application June 10, 1955, Seriai No. 514,585

25 Claims. (Cl. 340213) This invention relates generally to electrical networks and apparatus therefor, and more particularly, provides improved electrical networks and integrating means including relay mechanisms which may be connected to receive pulsations of energy from a primary (and usually, low energy) circuit and produce, through a related amplifying circuit, an action, which is an exact replica of conditions in the primary circuit, variations in any one or more electrical conditions of said primary circuit producing corresponding but amplified actions through said amplifying circuit. This application is a consolidation of the disclosures of the applicants copending applications, Serial No. 61,676, filed November 23, 1948, now abandoned, and Serial No. 168,393, filed June 16, 1950.

Primary objects of this invention are to provide improved electrical networks and an improved relay mechanism having the aforesaid characteristics; to provide such a mechanism which is operable to integrate a series of electrical impulses applied thereto irrespective of the nature of the factor which causes these impulses; and to provide an integrating apparatus operable to produce an action which exactly reflects any one or more electrical conditions or change therein, existing in an associated supply circuit, the action being either a mechanical action, an electrical action, or otherwise.

Another object of the invention is to provide an improved electrical control system incorporating improved amplifying means for actuating an alarm or other electroresponsive indicating element.

The drawings show preferred embodiments of the invention; however, it will be obvious to those skilled in the art that changes may be made in the specific embodiments shown without departing from the spirit and scope of the invetnion.

Figure 1 is a diagrammatic view of a network embodying the invention;

. Fig. 2 is a diagrammatic view of a modified network embodying the invention;

Fig. 3 is a plan view of a preferred construction of integrating relay embodying the invention;

Fig. 4 is a view in side elevation of the integrating relay with certain of the parts broken away for clarity;

Fig. 5 is a view taken along the line 55 of Fig. 3;

Fig. 6 is a view taken along the line 66 of Fig. 3;

Fig. 7 is a view taken along the line 7-7 of Fig. 3;

Fig. 8 is a view taken along the line 88 of Fig. 3;

Fig. 9 is a partial end view of the relay; and

Fig. 10 is a diagrammatic view of a gauging system embodying the invention.

Figures 1 to 9 are taken from application Ser. No. 61,676 and Figure 10 is taken from application Ser. No. 168,393.

Pulsating circuits embodying the present improvements may be specifically used for any one of a wide variety of purposes, and the integrating elements may be designed to respond to any one or more of a variety of maximum, minimum, and/or intermediate conditions. The actions produced by the integrating elements may be of various 'ice types, both electrical and mechanical actions being shown herein by way of illustration. In accordance with the illustrated embodiments of the present improvements, each pulse of current through the pulsating circuit actuates a relay mechanism, enabling the latter to correspondingly supply a pulse of current to integrating means which are illustrated as taking the form of a bimetallic element having a heater which receives a pulse of current each time the relay is actuated. With this arrangement, the electrical heating elements, and the bimetallic signal element, acquires a temperature which is a measure of the average flow of current through the circuit.

In the system of Figure 1, the present integrating mechanism is arranged to respond to and serve as a measure of the frequency of a series of pulsations occurring in a supply circuit, the pulsations being caused by a periodic mechanical action, such as the movement of the balance wheel of a clock mechanism. The relay mechanism thus measures the escapement rate of the clock mechanism.

More particularly, in Figure 1, the numeral 1 designates generally an optical system comprising a light source 2, a lens 4 for focusing the rays of the light source 2 through an aperture 5 of an oscillating balance wheel 8 of a clock mechanism, not otherwise shown, against a photoelectric cell V1. As this balance wheel 8 oscillates light will impinge upon the photoelectric cell V1 twice during each cycle of oscillation of the balance wheel.

The cell V1 is of the type in which a change in light intensity changes the voltage thereacross so that each time the light impinges on the cell V1 an electrical pulse is impressed on the condenser Cl which in turn changes the conductivity of the valve V2 which triggers the valve V3 whereby condenser C7 is allowed to discharge through the valve V3 and the winding or coil 24 of the integrating relay 20. This measured quantity of energy maintains the relay actuated for a predetermined time interval for flow of current through the heater or winding 26 of the bimetallic member 28 from the battery B2. As indicated in the drawing by the switches SW1 and SW2, the battery B2 may be used in parallel with the battery B1 or as a separate battery. It will be further appreciated that a single battery B1 could be used and battery B2 could be omitted. Or, if desired, battery B1 could be omitted and battery B2 be used. Also, if desired, battery B2 could be arranged in series with battery B1 for supplying energy to the relay 20. As the frequency of the oscillation of the balance wheel 8 increases the frequency of the energization of the heater 26 is increased and the higher will be the temperature thereof above ambient. As will be discussed below, in connection with the member 72, the bimetallic member 23 is of the compensated type and is unaffected by ambient temperatures, but is responsive to temperature rises above ambient temperature. The bimetallic member 28 thus takes up a flexed or warped position determined by the integrated value, or net heating effect thereon, of the succession of current impulses supplied to the winding 26. In the broader aspects of the invention, these movements of the member 23 may be utilized to perform any of a variety of actions, mechanical, electrical, or otherwise. In Figure 1, member 23 is arranged to energize an indicating light L1 when its temperature rise is below a predetermined value, and to energize an indicating light L2 when its temperature rise is above their predetermined value. When, however, the temperature rise is of the desired predetermined value, indicative of the desired rate of oscillation of the balance wheel 8, the member 28 is arranged to maintain both lights L1 and L2 de-energized. Additional lights may, of course, be provided to indicate intermediate conditions, or conditions at either side of the limits represented by lights L1 and L2 and, in fact, if a progressive and continuous indication is desired, member 28 may be arranged as the movin'g'element of-a rheostat. As isshown,"'also, in Figure 2, the member 28 may be directly utilized to control the position of the needle of a gauge or other indicator.

The amplified effect 'of the present relay mechanism, of course, permits relatively minute changes in the supply circuit to be reflected as relatively large changes in the amplifying'circuit,since the current in the amplifying circuitgthough controlled by the current in the supply circuit, can be of greatly amplified magnitude.

Still'more specifically, the cathode of the valve V1 is connected to the negative bus '12 by a conductor 14, While its anode is connected throu'gh'a resistor R1 to the movable tap 16 of apote'ntiometer resistor P1 and thence to the positive bus 18. The busses '12'and '18 are shown as supplied with electrical energy from a battery B1 but which could be supplied from'an alternating current rectifier or other source'if desired. The anode of the valve V1 is also connected through a condenser C1 to the control grid 'of the valve V2. A resistor R2 connects this control grid to the negative bus 12 whereby when the valve V1 is not conducting, that is, when light is not falling thereon, the valve V2 will be biased into a conducting condition. When, however, a light beam impinges upon the valve V1 and it conducts, the potential of the condenser C1 will be lowered, thereby placing a negative pulse upon the control grid of the valve V2 causing it to conduct less current and thereby the anode potential thereof will be raised. The valve V2 is connected intermediate the busses 18 and 12 as a pentode amplifier with R2 serving as a grid resistor, R3 serving as an anode resistor, and R4 serving as the cathode resistor by-passe'd by condenser C4. The screen grid of the valve V2 is connected through a condenser C5 to the bus 12 and through a resistor R5 to the bus 18 in a usual manner.

Valve V3 is of the discontinuous control gas-filled type which, when once rendered conductive, will conduct as long as the proper potential is maintained between its anode and cathode. The grid of the valve V3 is connected to the anode of the valve V2 through a condenser C6'and to the bus 12 through a resistor R6. The condenser C7 serves as the source of energy for the anode circuit of valve V3 which includes the winding 24 of the relay 6 and a current limiting resistor R7. The resistor R7 and condenser C7 are connected between thebus 18 and an adjustable tap 22 of a potentiometer resistor P2 connected between the busses 12 and 18, and the bus 18 through a resistor R8. The positioning of the tap 22 determines the charge which isplaced on the condenser C7 while the resistor R8 determines the rate at which the condenser C7 is charged; the value of R8 being such that during conduction of' the' valve V3 the condenser C7 cannot be charged at a sufiicient rate to maintain its charge above that necessary to cause the valve V3 to conduct.

Since the cathode of the valve V3is connected to the tap 22 through the winding 24, the potential thereof will be positive with respect to the bus 12. The resistor R6 will'normally maintain the potential of the grid of the valve V3 suflicientlynega'tive with respect to that of the cathode-sothat the valve V3 will normally be nonconduct1ve. When, however, the potential of the'condenser C6 is suddenly increased due to the lowering of the conductrvrty of the valve V2 by the-valve Vi, the potential of the grid of valve V3 'will be raised sufficiently to trigger or fire the valve V3 whereby the condenser C7 is discharged through the Winding 24 of the relay 20.

Therefore, when a light beam impinges upon the oathode of the valve V1 and it begins to conduct, the potential. of the condenser C1 and of the control grid of the valve V2 will be lowered thereby causing the valve V2 to decrease in conductivity and increase the potentialof the condenser C6 associated with the anode of the valve V3.

This increase in potential of the control-grid of a valve V3 will cause it to conduct and discharge the condenser C7 through the relay 20. Upon being rendered conductive, current will continue to flow until the condenser C7 is discharged, thereby maintaining its contacts 3032 (Fig. 1) or 184186 (Fig. 2) closed for a predetermined time interval, permitting current to flow from the battery B2 through the heater winding 26 through the now closed relay contacts 30-32 back to the battery B2. As the temperature'of the bimetallic member 23 increases, it will tend to warp to the right, Fig. 1, whereby thec'ontacts 34 and 36 are opened de-energizing the light L1. If the frequency of discharge of the valve V3 is sufiiciently high, the temperature of the bimetal 28 will rise to a predetermined higher temperature whereby the contacts 384t) will close, thereby energizing the telltale light L2. The circuit for the lights L1 and L2 extends from the battery B2 through the bimetal 23 through the contacts 34- 36 and 38-40 respectively and to the battery B2 through the common bus 42.

In the foregoing system, the voltages of batteries B1 and B2 being assumed as'constant,'and it being assumed the condenser C7-has'a uniform charge at the beginning of each discharge action, the'successive pulsations supplied to-heater winding 26 are of constant magnitude. The integrating mechanism 'thus serves as an accurate measure of'the frequency of the pulsations, and of the oscillating frequency of balance wheel 8.

In other syst'eins'to which the present relay mechanism is applicable, the primary circuit maybe subject to a varietyof changes which individually and/or collectively affect the average value of the current flowing therein. For example,"the maximum-instantaneous current values may'change because of'changes in applied voltage or otherwise; the frequency may change; and for a given frequency, the ratio between the lengths of conducting and non'-conducting intervals (or of maximum and minim'umcurrent flows) may change. 'Figure 2 illustrates an'application of the invention in which both the upply and amplifying circuits derive energy from the 'same'source and in which the net heating effect imparted to the'bimetallic member by its heater winding, is 'at all times directly, proportional to the net heating e'fiect' of the current flowing in the primary circuit, The temperature rise, above ambient, of the bimetallic member, is thus an exact-measure of thenet heating efiect of the supply-current as well, of course, as serving as a measure of "the average value of such current. Any change jinoper'atin'g conditions in'the supply circuit which affects in any way the'aver'age value of current'flowing therein is exactly reproduced, on an amplified scale, in the arnplifyin g circuit More particularly, in Figure 2, battery B supplies a load which is pulsating in character and may, for example, be a load which itself periodically makes and breaks the battery circuit so that the current in the battery circuit is constituted by a succession of spaced impulses, each impulse, for a given battery voltage, being of the same magnitude. The'nature of the load may, however, vary the frequencyof the pulsating primary current and, for a given frequency, the ratio between the lengths of conducting-and non-conducting intervals may vary. Finally, it may be assumed'that the battery voltage itself is subject to variation. 7

The relay winding is connected'in series with the battery B and with the load. 'When energized, the relay closes its-normally open contacts 184-l86, and completes an energizing circuit for the heater winding 74 associated with a bimetallic member 72. One end of the 'heater winding is connected to the bimetallic member, which memberin turn'is connected to the ungrounded battery terminal. Consequently, "each impulse of current transmitted throughtthedoad causes a momentary closu're of contacts:184- 1-36, 'enabling the battery to pass an impulse of current through the heater winding 74.

Each such impulse experienced by the heater winding 74 is of the same duration as the impulse experienced by the load, but may, of course, be of greatly amplified magnitude. If the load characteristics change the frequency or the ratio between the lengths of conducting and nonconducting intervals, the heating effect of the current impulses experienced by the heater winding 74, are correspondingly varied. Similarly, if the battery voltage varies, the magnitudes of individual current impulses supplied to the load and to the heater winding 74 are correspondingly and proportionately varied. Accordingly, the net heating eiiect imparted to the bimetallic member is a direct measure, on an amplified scale, of the heating effect of the currents flowing in the primary circuit.

In Figure 2, bimetallic member 72 is diagrammatically shown as directly controlling a gauge needle g, and as also controlling a pair of contacts 78-79. Contact 78 is electrically connected, through the body of the bimetallic member 72, to the battery B, and contact 79 is connected through an indicating light to ground. Depending upon the disposition of the bimetallic member 72 therefor, light L is operative to indicate either a desired minimum or maximum average current in the primary load circuit.

Figures 3 through 9 show a preferred construction of the relay of Figure 2, except that the bimetallic member serves only to control contacts 78-79, and does not provide for the operation of the gauge needle g. More particularly (Figs. 3-9), the relay unit comprises a U-shaped magnetic member 80 having substantially parallelly extending side elements 81 and 82. An armature 86 is pivotally secured at one end portion 88 to the element 82 adjacent its free end portion 94 by means of a flexible, metallic bracket member 90. The armature 86 is operable to pivot on the bracket and closes a magnetic circuit through a U-shaped member 80 under the influence of an electric magnet 96. The magnet 96 is of the usual construction and has a central core 98 carrying a magnetic coil 1520 and is positioned within the U-shaped member 84) between the parallelly extending elements 81 and 82 and held therein by one end of its core 98 which is riveted as at 102 to the connecting portion 84. One end of the coil is connected by means of a lead Wire 1194 to terminal 76, while the other end is connected by means of lead Wire 106 to terminal 108.

Referring again specifically to the construction of the integrating unit, the elements 81 and 82 have oppositely extending outwardly projecting marginal flange portions 114 and 116 which support the terminals 76 and 198 respectively and also terminals 118 and 122 respectively.

The terminal 118 is substantially platelike and has an olfset portion 120. A hollow rivet 131 extends through aligned apertures 123 of the flange portions 114 and 124 and secures the terminal 118 in electrical conducting relation with the member 8!).

Terminal 76 is platelike and is secured by a hollow rivet 126 extending through aligned apertures in terminal 76 and flange portion 114. Fiber Washers 128 are positioned on either side of the terminal 76, and a cylindrical member 130 surrounds the hollow rivet 126 whereby the terminal 76 is insulated from the member 80.

The terminal 122 comprises a metallic, L-shaped strip member having a leg portion 132 extending vertically upwardly from the plane of the flange portion 116 and having its other leg portion 134 extending parallelly to but spaced above the flange portion 116 by a fiber insulating member 136. The leg portion 134 of the terminal 122 has a laterally extending lug 138 (Fig. 3) which carries a wire attaching screw 140 for conveniently attaching a lead wire thereto.

The terminal 108 comprises generally an L-shaped strip metallic member having one leg portion 142 extending vertically upwardly from the flange portion 116 and substantially parallel to but spaced from the leg 132 of the terminal 122. The other leg portion 144 extends above and substantially parallel to the leg 134 and is insulated therefrom by an insulating strip member 146. The leg 144 has a laterally extending flange portion 148 similar to portion 138 but spaced therefrom and carries the screw 109 by which a lead wire is attached to the terminal 108.

An L-shaped metallic member 156 has one of its legs 158 extending substantially perpendicularly to the plane of the flange portion 116 adjacent the open end of the U-shaped member 80 and has its other leg 160 positioned above and extending substantially parallel to the legs 134 and 144, but is spaced therefrom by an insulating strip member 162. The legs 134, 144, and 160 and flange portion 116 have aligned apertures extending therethrough for receiving hollow rivets 164 and 166 which secure the legs together and to member 80. Cylindrical insulating sleeves 168 and 170 surround the rivets 164 and 166 and cooperate with the members 136, 146, and 162 and fiber washers 172 to electrically insulate the various L-shaped members from each other and member 80. Intermediate the lower flanged portions of the rivets 164 and 166, and the fiber washers 172, are positioned metallic washers 174 to aid in flanging the rivets 164 and 166. Washers 161 and 163 are interposed between the tubular rivets 166 and 164 and the adjacent insulators such as 162.

A flexible contact member-carrying arm 1% is suitably secured to the armature 86 adjacent the hinge bracket portion 90 and extends along in front of the armature 86 terminating in an offset portion 182 which carries contact member 184. Pivotal movement of the armature 36 toward its bridging position of the openend portions of the U-shaped member 80 causes the contact member 184 to en age a contact member 186 carried by the perpendicularly extending leg 158 of the member 156 so that upon energization of magnet 96 the circuit which is controlled by the contact members 184 and 186 will be completed to energize the heater winding 74 carried by the bimetallic member 72. Contact 182 is electrically connected to the ground terminal 118, through members 82, 86 and 180.

The bimetallic member '72 is of substantially lJ-shape metallic, having substantially parallelly extending legs 1% and 192 and an integral connecting portion 1%. The free end portion of the leg is carried by the arm or leg 142 of the terminal and is electrically connected thereto by a rivet and a pair of metallic washers 196. The electrical coil '74 is carried by the other leg 192. One terminal of the coil 74 is connected to leg 1% and consequently to terminal 163. The other terminal of the coil is connected through members 160-158 to terminal 186. Thus coil 74 is adapted, upon closure of contact members 184 and 136, to heat and warp the leg portion 192 so that contact member 73 carried thereby at its free end will engage contact member 79 carried by the perpendicularly extending leg portion 132 of the terminal 122. The transverse connecting portion 194 of the bimetallic member 72 preferably has a laterally oiiset portion 284 which adds rigidity thereto.

Each time current flows through the coil 190, the armature 86 of the integrating relay will pivot toward its bridging position relative to the legs 81 and 82 of the U-shaped member 8i causing the contact members 1% and 136 to engage. Closure of the contact members 184 and 186 closes the heater energizing circuit for the heater coil 74 of the integrating mechanism 72, and current will flow from the battery B2 through the grounded terminal 118, member 81), bracket member 90, arm 1813, contact member 184, contact member 186, the bracket member 156, to lead Wire 2200 of the coil 74, coil '74, bimetallic member 72, leg 142 of the terminal 108, back to the battery B2. Flow of current through the heater coil '74 causes the leg 192 of the bimetallic member 72 to assume a temperature proportional to the average "aytscisss currentfiow through the windingfttltl. Thisp'ropor'tional temperature is so chosen that, at a, predetermined tempermute, the contact 'm'einber'73 carried by the legi92' will iengagethe contact'member W carried by the arm 132 of the terminal 122' to energize the light L. Upon closure of the light circuit, current flows from ground, through the lamp L, terminal 122, contact member '79, contact member 78, bimetallic member '72, 'and terminal 198, back to the battery B2.

The relay structure'shown in Figures 3 through 9 may,

of course, be used with the'system of Figure 1, in which event winding 1% would replace winding 24, and leads 194 and res, associated with winding lild'would'be connected to the terrnina'ls 22a and 22b of Figure l.

Anotherembodiment of the invention is illustrated in Fig. 10, .this'embodiment being directed to automotive au in -s stems of the re ulated-current t e for augb O U ing an operating'conditions of the vehicle, such as, fuel level, oil pressure, engine temperature and the like. This embodiment of the invention is particularly characterized as embodying an indicating or alarm circuit which is actuated in the event the operating condition'reaches a critical value.

Electric gauging systems of the regulating-current type, but lacking in the hereinafter described signal mechanism, are widely used in the automotive held for providing continuous indications of fuel level, oil pressure, and engine temperature. Basically, these systems include a thermally responsive sender which is actuated by the particular condition being gauged and transmits electric energy in pulsating form, the average value of which is a measure of the condition being gauged, This pulsating energy is received by a thermally responsive receiver which indicates the average value of the energy.

In most motor vehicle systems, the voltage appearing across the terminals of the battery varies widely due to the charged condition of thebattery and also due to the effect of the usual battery charging generator which nor-' mally isdriven at'a speed proportional to the engine speed and which engine speed is continually varied from an idling speed to a full speed. The sender acts to transmit an amount of electric energy to the receiver which is independent of the battery voltage and is just sufficient to maintain the sender at a temperature which is proportional to the magnitude of the characteristic to which it is sensitive. Since the receiver is connected in series therewith its temperature is a function of that of the sender and, when properly calibrated, gives a direct indication of the magnitude of the characteristic to which the sender is responsive.

This embodiment of the invention particularly contemplates the addition to such a system of a relay mechanism which has an actuating coil connected in series with the sender and receiver, so as to be energized concurrently therewith. The relay mechanism correspondingly energizes a second electric heater for heating a third ambient temperature compensated bimetallic heat responsive member which acts at a predetermined selected temperature to close an alarm circuit. Energization of the alarm indicates that a predetermined magnitude of operating condition has been reached, such as, for example, an undesirably low fuel level.

Because of the inherent nature of the electrical systerns associated with the motor vehicle and the general use of a nominal six volt storage battery, serious problems are presented with respect to the power available to operate the gauging systems of the above type. With such a low voltage supply there is a limit in the number of electrical elements which may be connected in the same series circuit, if sufiicient power is to be provided for positive actuation of each of theseries arranged elernents.

fuellevel condition by"rneans ofa'fioat arm 203 and 8 energized -rmm fa "suitable source of electrical energy such as" a storage'battery "2ll5fthe' output" voltage of which may be'widely variable-as foreirample due to theactic'n or a charging generator (not shown) or other load being suppliedthereby. "The'system comprises a sender 256, a receiver 2tl8,'a relay 21tiand an integrator'2l'2'for actuatinganalarm'or signal2i4. Senders and receivers of this type are'readily obtainable in the open market and they are therefore only diagrammatically shown herein, and only 's'ufiicient description'thereof will be herein given as is necessary to'describe this invention.

The sender"2ll6"comprisesa thermally compensated bimetallic'menflaeror element 216 suitablycarried by a support 218 which may be of electrically insulating material whereby the member-216 is'electrically insulated from ground or other metal vehicle parts. An electrical heater winding 22% is arranged in heat exchange'relation with the member 2l6 and'has one terminal connected to a contact 222 carried by the free end of the member 216. If desired the connection to the-contact 222 may be through the bimetallic member asshown, or it'could be directly to the contact 222 in which event the contact 222 might'be electrically insulated from the member 216.

If the contact 222 is so insulated the member 216 need not necessarily be insulated from the-rest of the metal motor vehicle parts. A positionable contact 224 engageable bythe contact '222 is electrically connected by a conductor 2-26 to one terminal 228 of the storage battery 205. 'As'will be seen from the diagrammatic representation, the arm 2% will position the positionable contact 22d'in accordance with the level of the fuel 23%).

The receiver 208 comprises an ambient temperature compensated bimetallic member or element 232 suitably secured to a'fixed support 234- and provided with a needle "or pointer 236 which cooperates with suitable indicia 2353 upon flexing of theelernent 232 in response to changes in temperature'thereof' imparted by an electrical heater winding 240to indicate the level of fuel 23b. One terminal or" the heater 2% is connected to the remaining terminal of the heater22tl'and the other terminal of the heater 24% is connected to one terminal 242 of the energizing coil 24% of the relay 219. The other terminal 246 ofthe coil- 244 is connected by a conductor 243 and switch 250 to the other terminal 252 of the battery 2%. As shown, the'con'ductor 226 maybe electrically connected to the metal parts'of the motor vehicle or other assemblage "with whichthe gauging circuit is associated to form aground connection.

The relay Zitl'coinprises the aforesaid coil 244, the energization and de-energization of which acts through contacts 256-258, to close and openan electric circuit to the electrical heater'winding 26% associated with an ambient temperature compensated bimetallic element 254 -of an integrator 212. The contact 253 is connected to ground and therethrough to the terminal 228 of the bat- "tery 205 While the contact 256 is connected to one terminal of the heatenZtl. The other terminal of the heater 260 is connected, through element 254, to conductor 262,"and thence, through the conductor 248 and switch 251) to the'ungrounded terminal 252 of'the battery 205.

The alarm circuit comprises an alarm 214 which may bear light or may be'any other kind ofsi'gnalling'device capable ofgiving a signal, visual, audible, or otherwise to inform a'person that it has been energized. One terminal of the alarm 21 iis connected to ground while its other terminal is connected through contacts 264 and 266 and element-254 to conductor 2 62 and thence, as above described, to the battery terminal 252. The contact 26 5 is relatively fixed or adjustably positioned to be engaged by contact 266 at a predetermined integrated value of the energy supplied to the heater 26d.

7 The sender 2tl6,receiver 2%, and integrator 212 act toiintegrate the effects of the respective'pulsating current flows therethrough and therefore respond not to instantaneous currents but to integrated average current flows.

It is believed that the remainder of the details of construction may best be understood by a description of the operation of the system which is as follows:

Under normal de-energized condition of the gauging circuit, with the switch 250 open, the bimetallic element 216 will be at a temperature to maintain the contacts 222 and 224 in closed circuit condition. The relay coil 244 will be de-energized so that the contacts 256 and 258 will be in open circuit position. The bimetallic element 254 will normally maintain the contacts 264 and 266 in a closed or engaged position. However, since the switch 250 is open, no signal will be registered by the alarm 214. Upon closure of the switch 250, current flows from the battery terminal 228 through the conductor 226 through the contacts 222 and 224, the series connected heaters 220 and 240, the relay coil 244, conductor 248 and switch 250 to the other battery terminal 252. This flow of current immediately energizes the coil 244 and causes the contact 258 to engage the contact 256, and complete a circuit from the battery terminal 228 through ground contacts 256 and 258, heater 260, bimetallic element 254, conductors 262 and 248, and switch 250 to the battery terminal 252. Energization of the heater 269 raises the temperature of the bimetallic element 254. If the level of the fuel 230 is above the critical value for which the integrator 212 is set, the temperature of element 254 will rise high enough to move the contact 266 out of engagement with contact 264 and de-energize the alarm 214. The opening of the contacts 266 and 264 will occur very promptly upon closure of the switch 250 and any signal initially given by the alarm 214 will be quickly terminated.

Energization of the heater 220 will immediately act to elevate the temperature of the bimetallic element 216. When element 216 has reached a temperature which exceeds ambient by an amount corresponding to the then existing fuel level 230, it will move contact 222 away from the contact 224 and de-energize this circuit. The bimetallic element 216 will thereafter cool and cause the contact 222 to re-enegage the contact 224. This intermittent opening and closing of contacts 222 and 224 will continue as long as switch 250 remains closed. Sender 206 thus passes just sufficient energy to maintain element 216 at a temperature which exceeds ambient by an amount which is determined by the position of the float arm 203. The required amount of energy is, of course, independent of the voltage of the source, but varies with changes in the position of arm 203.

During each period in which the heater 220 is energized, the heater 240 is similarly energized since it is in series circuit therewith. Thus, a heating eflect proportional to the heating effect of the heater 220 will be imparted by the heater 240 to the bimetallic element232, and the latter will be maintained at a temperature which is proportional to the temperature of the bimetallic element 216.

As aforesaid, the average energy required to maintain the bimetallic element 216 in the described condition, in which it alternately opens and closes the contacts 222 and 224, is determined by the float arm 203. In turn, the rotative position of the arm 203 is determined by the level of the fuel 230. As the fuel level increases, the arm 203 moves the contact 224 upwardly whereby the bimetallic element 216 must be warped further to cause the contact 222 to disengage from the contact 224. This action correspondingly increases the average value of the energy transmitted by the sender to the receiver. Conversely, as the level of the fuel 234) lowers, the float arm 203 will lower the contact 224, whereby less flexing of the bimetallic element 216 is required to move the contact 222 out of engagement with the contact 224. This decreases the average value of the energy transmitted to the receiver.

Each engagement of the contacts 222 and 224 causes a corresponding engagement of the contacts 256 and 258,

and so causes the heater 260 to be energized each time that the heaters 220 and 240 are energized, and for like time intervals. is the same as that supplied to the series circuit including the heaters 220 and 240 and coil 244. As in the case of receiver element 232, the temperature attained by the bimetallic element 254 is a function of the temperature of the bimetallic element 216. Thus, the displacements of elements 232 and 254 are continuously proportioned to each other and to the temperature of element 216. The position of the contact 254, which may be adjustably controlled by suitable means not shown, is selected so that when the fuel level 230 falls to a predetermined low level, the temperature of the bimetallic element 254 is not sufiicient to hold the contact 266 out of engagement with the contact 264. Under such conditions, the alarm 214 will be energized.

it will be noted that, as shown, the alarm 214 is energized at a predetermined low fuel level. This same general circuit arrangement, however, may be used when a difjerent response is desired. For example, the bimetallic element 254 may be reversed so that it moves the contact 266 toward contact 264 upon an increase, instead of a decrease, in the average value of the energy supplied to the heater 260. Again, the bimetallic element 254 could be provided with a second contact on the face thereof opposite to the contact 266 and a second adjustably positioned contact, similar to the contact 264, which may be engaged upon warping of the bimetallic element 2'54 in the clockwise direction.

The coil of relay 210 is designed to abstract very little electrical energy. It may be added to the gauging circuit comprising sender 206 and receiver 208 without materially increasing the total energy consumed therein.

Since the heater 260 is directly connected across the battery 265 when contacts 256253 are closed, the integrator may be supplied with sufficient energy to cause positive circuit control between contacts 264 and 266. Relay 21t and integrator 212 thus act as an amplifier, and the heater 260 and the bimetallic element 254- may be so proportioned that the movement imparted to contact 266 in response to any given percentage change in fuel level is substantially greater than that of the receiver 208. This enables a very accurate control of the point or points at which the contacts 264 and 266 engage or disengage.

It will be understood that the relay mechanism illustrated in Figs. 3-9 may also be used in this embodiment of the invention.

What is claimed is:

l. in. an electrical network for association with a source of electrical potential the magnitude of which may be Widely variable, a first circuit arranged to be energized from said source, ambient temperature cornpensated means providing a pulsating flow of electrical energy of a controlled but variable frequency through said circuit and current flow responsive means associated with said circuit and actuating a pair of contacts, said flow responsive means acting in response to current flow in said circuit to actuate said contacts for each said flow of said pulsating energy, a second circuit energized with a potential of a magnitude proportional to that of such source and including said contacts, and an integrating means for int-e rating the magnitude of average energy flow through said second ccircuit.

2. In an electrical network adapted to be energized from a source of electrical energy, a first circuit including ambient temperature compensated means to provide a series of electrical energy pulses of a controlled but variable frequency to flow through said circuit from such source, electroresponsive control mechanism having an actuating portion responsive to each flow of energy through said circuit and including a pair of contacts actuated as a consequence of each response of said actuating portion to such energy flow, an integrator, a

The voltage supplied to the heater 260.

ecesses "'secoiidcircuit-adapted to be sup'plied fromsuch source i and including -said contacts and" said integrator whereby said integrator is energized as-a function of the actuation of said contacts.

' 3. The combinationof claim 2-in which said ambient temperature compensated -means-acts toprovide energy pulses of amagnitude which is'a function of the potentialof such source.

4. A signal system for indicating the existence of a predetermined averagerate of energyflow in an electrical circuit carrying a pulsating current of a controlled but variable frequency,-including a second circuit containing a switch having a pair of cooperatingsswitch contacts for opening-and closing saidcircuit,means including an electroresponsive element connected in the-first circuit for actuating-said switch, athird circuit, an electrically operated signalling device connected in the third circuit,

and a delayed a'ction heat responsive relay for controlling the energization of the third circuit and having its heating element'connected in the second circuit, and means 1 adapting at least said first and second circuits for connection to a common source of electrical energy.

5. A signal system for indicating the existence of a predetermined average rate of energy flow in a first electric circuit conveying pulsating electrical energy from a source-of electrical potential including a second electric circuit energized from said source of electrical energy but which is connected to said source independently of said first circuit, an electrical relay actuated by said first circuit and controlling energization of said second circuit, said relay comprising an. electroresponsive actuating element energized by saidfirst circuit, a third electric circuit energized from a source of electrical energy, a

delayed acting relay actuated by said second circuit for controlling the energization of said third circuit, said second named relay having an electroresponsive actuating device including a bimetal, said device being connected to said second circuit whereby said bimetal is heated as a consequence of the energization of said second circuit to=assumeawarped position which varies as a function of the magnitude of the average value of the energy-supplied to said device as a consequence of the operation of said first named relay, said second named relay also including a pair of contacts controlling energizetion of said third circuit, said contacts being relatively movable as a consequence of the warping or" said bimetal to control the energization of said third circuit, and a signalling'device controlled by said third circuit.

6. An electrical measuring system comprising a first electric network having sensing means "responsive to the magnitude of the measurement being examined and controlling electrical energy flow of a variable frequency through said network, said sensing means acting to provide an average energy flow magnitude in said network which is proportional to the magnitude of the measurement, an electric relay having a heat responsive circuit actuating mechanism and a pair of electrical contacts movable to a predetermined relative position as a consequence of said heat actuated mechanism attaining a critical temperature, means interconnecting said heat responsive mechanism with said network to energize said heat actuated mechanism as a function of the energy flow in said network whereby the temperature of said heat actuated mechanism 'is a function of the average energy flow in said network, said heat actuated mechanism being teated to said critical temperature as' a consequence of "the maintenance of a'predetermined average energy flow in said first network, and a second network including a signalling device and said contacts,-said second network acting in response to the maintenance of said contacts in said predetermined position to energize 'said signalling device.

" 7. The combination of claim 6 in which said sensing "means provides a continuingseries'of energy pulsesin saidfi'rst named networkof a frequency which is a tune- 112 tiom ofthe:magnitude/refil emeasurement being examined saidameans which interconnectsz said heat responsive mechanismgof said relay. including: an electro-responsive element connectedinisaidfirst named network and apair of electrical contacts actuated'to closed position to energize said heat responsive mechanism .upon .the. occurrence of each said energy .pulse.

8. The combination of claim 7 in whichithe electrical energy for said first named network and for said heat responsive mechanism is derived from a common source of potential. V

9. An electrical control system comprising anarnbient temperature compensated current pulsing mechanism for supplying a series of currentpulses of controlled but variable 'durationand frequency, electroresponsive control mechanism responsive to current flow, a circuit for supplying pulses of current to said electroresponsive mechanism under control of saidpulsing mechanism, a temperatureresponsive member,-and current flow controlling means actuatedby said electroresponsive mechanism to "provide-a pulse' of heat to said temperature responsive-member each time said electroresponsive mechanism receives a pulse of current, the relative magnitudes, frequency and "duration of said. pulses of current and pulses of heat being so related to each other that said member is heatedto a temperature which is a function ofthe average value of the pulsating current.

10. Integrating relay mechanism for use with an elec- 'trical network adapted tobe'supplied from a source of 'means includes a'heat storage element and a heater therefor which receives said energy in the form of current impulses.

'12 An electrical control. systenr comprising a current pulsing mechanism for-supplying a series of current pulses of a controlled but variable frequency, electrotresponsive' control mechanism responsive to current flow, a circuit'for supplying said pulsesof current to said electroresponsive'rmechanism .under control of said pulsing zmechanisrri; a temperature responsive member, current flOW COHHOlIiHg means actuated by said electroresponsive mechanism-to provide pulses of heat to said temp-rature responsive-member of the same frequency as the pulses supplied bysaid current; pulsing mechanism, the heating value ofsaid pulses -supplied'by said pulsing mechanism being so related to the heating value of said pulses of heat that said member is, heated to a. temperature which is a function of the average value of the said current pulses, .andmeans actuated by said member, as determined by the .temperaturelthereof for. controlling an electrical .circuit.

113. electrical control system comprising a-current pulsing mechanism for supplying aiseries of current pulses 0f. a controlled butvariable frequency, electroresponsive control mechanism, a'circuit for supplying said pulses of current to; said" electroresponsive. mechanism under control fofisaid. pulsing mechanism, a bimetallic element, a heater-means for said element, means actuated bysaid 'electroresponsive-mechanisnr as a consequence of said pulses of current flowing therethrough for controlling the ilowof -a -pulsating=currentto said heater, the-heating 13 being so related to the heating value of said pulsating current that said bimetallic element is heated in accordance with the average value of the pulsating current, and means operated by said element as determined by the temperature thereof for controlling an electrical circuit.

14. In an electrical system, an ambient temperature compensated pulsing mechanism adapted for connection to a source of electrical energy for causing a series of current pulses of a controlled but variable frequency to flow through the system, said frequency being a function of the magnitude of a controlling characteristic being gauged, a relay mechanism having an operating coil connected to respond to current flow through the system and having switch means actuated as a consequence of each pulse of current flowing through said coil, an electric circuit also adapted for connection to said source and having the current flow therethrough controlled by said switch means, a heated integratnig element, and electrical heater means in said circuit and arranged in heat-exchange relation With said element in such relation that the temperature of said element is a measure of the average value of said series of current pulses.

15. In an electrical network for measuring a variable physical condition, and adapted for association with a source of electrical potential the magnitude of which may be widely variable, a first circuit arranged to be energized from said source, temperature actuated switch means controlling energy flow through said circuit and including means for supplying energy to actuate said switch means as a function of the flow of energy through said circuit, said switch means acting to pulsatingly control the flow of energy through said circuit to provide an average flow which is independent of variation in magnitude of said potential, integrating means in said circuit directly connected to the energy supply means of the switch means to indicate the magnitude of said flow, current flow responsive means associated with said circuit and actuating a pair of contacts, said flow responsive means acting in response to current flow in said circuit to actuate said contacts, a second circuit energized with a potential of a magnitude proportional to that of such source and including said contacts and a second integrating means for integrating the magnitude of average energy flow through said second circuit, means adapted to respond to said variable condition for regulating said temperature actuated switch means to correspondingly vary said predetermined flow, and means actuated by said second integrating means as a consequence of a predetermined average flow through said second circuit.

16. In an electrical network, a source of electrical I energy the potential of which may be widely variable, an electrical switch, a temperature responsive actuator for said switch and operable upon an increase in temperature to open said switch, means responsive to a condition to be indicated and operably connected to said actuator to adjust the temperature at which said actuator actuates said switch, a first electric heater for said actuator, a temperature responsive element, a second electric heater arranged in heat exchange relation with said element, an electroresponsive control mechanism having an actuating winding and a temperature responsive element arranged in heat exchange relation with a third electric heater and a pair of contacts actuated as a function of the energized condition of said winding, conductor means connecting said source, said switch, said first heater, said second heater and said winding into series circuit, conductor means connecting said mechanism heater and said mechanism contacts and a source of potential in series circuit, and alarm means actuated by said mechanism temperature responsive element as a consequence of its being raised to a predetermined temperature by said mechanism heater.

17. In an electrical network for measuring a variable physical condition and adapted for association with a source of electrical energy the potential of which may be widely variable, an electrical switch, bimetallic actuator for said switch and operable upon an increase in temperature to open said switch, a first electric heater for said actuator, means responsive to a variable characteristic to adjust the temperature at which said actuator opens said switch, a bimetallic element, a second electric heater arranged in heat exchange relation with said element, an electroresponsive control mechanism having an actuating winding and a bimetallic element arranged in heat exchange relation with an electric heater and a pair of contacts actuated as a function of the energized condition of said winding, conductor means connecting said source, said switch, said first heater, said second heater and said winding into series circuit, conductor means connecting said mechanism heater and said mechanism contacts and said source in series circuit, and alarm means actuated by said mechanism bimetallic element as a consequence of its being raised to a predetermined temperature by said mechanism heater.

18. In an electrical network for association with a source of electrical energy the potential of which may be variable, an electrical circuit adapted for connection to said source for energization thereby, control means controlling the flow of electrical energy through said circuit whereby said circuit is pulsatingly energized and caused to pass an amount of energy which is independent of variations in the potential of said source, means adapted to respond to changes in a varying characteristic for adjusting said control means to thereby regulate the magnitude of the average flow of energy through said circuit as a function of such characteristic, integrating means associated with said circuit, said integrating means hav ing a sluggish action whereby it acts to integrate the pulses of said energy over a time interval, an electroresponsive means associated with said circuit and provided with switch means actuable as a consequence of a flow of energy through said circuit, a second circuit including a second integrating means having a sluggish action for integrating pulses of electrical energy and energized with a potential which is a function of the potential of said source, and means actuated by said second integrating means as a consequence of a predetermined magnitude of average energy flow through said second circuit.

19. The combination of claim 18 in which said lastnamed means comprises an electrical circuit including an indicating mechanism.

20. An indicating system for indicating the magnitude of a variable condition, a storage battery connected to be charged from a generator, a relay having a winding, a first electrical circuit comprising a pair of electrical resistance units and said relay winding arranged in series circuit across such battery, a pair of bimetallic members, one of said members being arranged in heat exchange relation with one of said units, a second of said members eing arranged in heat exchange relation with a second of said units, a switch actuated by said one member and controllingthe energization of said circuit, means responsive to the magnitude of such condition and operably associated with said one member to control the temperature at which said one member actuates said switch, means actuated by said second member for giving a visual indication which is a function of the temperature of said one member, said relay being provided with a pair of contacts controlled as a consequence of the energization of said winding, a second circuit comprising an electric resistance unit and said contacts and energized from such battery, a bimetallic member in heat exchange relation with said last-named unit, and an alarm mechanism t actuated by said last-named member as a consequence of said last-named unit being energized by a predetermined magnitude *of average energy.

21. An indicating system for indicating themagnitude of a variable condition, a relay having a winding, a storage battery connected to be charged from a generator, a first electrical circuit comprising a pair of electrical resistance units and said relay winding arranged in series circuit.

across such battery, a pair of ambient temperature compensated bimetallic members, one of said members being arranged in heat exchan e relation with one of said units, a second ofsaid members being arranged in heat exchange relation with a second of said units, a switch actuated by said one member and operable to d e-energize said circuit at a predetermined temperature thereof above ambient temperature, means responsive to the magnitude of such condition and operably associated with said one member to control the magnitude of said predetermined temperature above ambient temperature at which said one member actuates said switch, means actuated by said second member for giving a visual indication which is a function of the temperature of said one member, said relay being provided with a pair of contacts controlled by said winding, a second circuit comprising an electric resistance unit and said contacts and energized from a potential proportional to that of such battery, an ambient temperature compensated bimetallic member in heat exchange relation with said last-named unit, and an alarm mechanism actuated by said last-named memberot asa consequence of said last-named unit reachinga predetermined temperature with respect to ambient.

22. In an electrical apparatus for measuring a variable physical condition, and adapted to be connected with a source of electrical potential the magnitude of which may be widely variable, a measuring circuit for measuring the magnitude of said condition, including means for causing a series of electrical impulses to flow in said circuit, an indicator having means for integrating said impulses and for actuating means for indicating the magnitude of the condition, a signal circuit for actuating a signal, indicating that the predetermined value of said condition exists, including a signalling device and a first switch vfor connecting said device to the source of electrical potential, a third circuit for actuating said first switch including a second integrating means and a second switch for connecting said second integrator to the source of potential,

an electromagnetic relay for actuating said second switch, including relay and a winding, said winding being connected in the measuring circuit to be energized by the said electrical impulses, so that each impulse flowing in the measuring circuit will be reproduced and caused to flow in the third circuit whereby the average wattage value of impulses flowing in the third circuit is proportional to the wattage value of impulses flowing in the measuring circuit, and the integrated value of wattage afiectingthe second integrator corresponds to the value of wattage affecting the indicator integrating means for any given time period.

23. in an electrical apparatus for measuring a variable physical condition, and adapted to be connected with a source of electrical potentialthemagnitude of which may be widely variable, a measuring circuit for measuring the magnitude of said condition, including means for causing a series or" electrical impulses to flow in said circuit, an indicator having means for integrating said impulses and for actuating means for indicating the magnitude of the condition, means responsive to variations of the condition, for causing the values of said impulses to be proportional to the existing condition, a signal circuit for actuating a signal, indicating that the predetermined value of said condition exists, including a signalling device and a tirst switch for connecting said deviceto the source of elec-H lo trieal potential, at third circuit for actuating said first switch including a second integrating meansanda second switch for connecting said second integrator to the source of potential, anelectro-magnetic relay for actuating said second,switch, including relay and a winding, said Winding being connected in the measuring circuit to be energi zed by the said electrical impulses, so that each impulse fiowingin the measuring circuit will be reproduced and caused to fiow in the third circuit whereby the average wattage value of impulses flowing in the third circuit is proportional to the wattage value of impulses lion-ing in the measuring circuit, and the integrated value of wattage afiecting the second integrator corresponds to the value of wattage affecting the indicator integrating means for any given time period.

v24. An integratingrelay apparatus comprising a substantially U-shaped member having substantially parallelly extending side elements and an integral base element joining-said side elements, an armature pivotally secured to one of said side elements adjacent one end thereof and adapted to pivot into a position bridging theadjacent ends of saidrside elements, an electromagnet carried by said base elementintermediate said side elements and operable when energized to pivot said armature toward its bridging position, corresponding edge portions of said side elements having oppositely extending outwardly projecting marginal ilange portions, a first supporting member, a first contact member carried bylsaid supporting, member, a second contact member carried by said armature and operable upon movement of saidarmature towardits bridging position to engage saidfirst contact member, a second supporting member supported by said U-shaped member, a substantially U-shaped bimetallic element having substantially parallelly extending legs, means securing one of said legs to said second supporting member, a third supporting member supported by said U-shaped member,

a third contact member carried by said third supporting member, an electric heater elementadapted to heat the other of said legs, a fourth contact member carried by said other leg and operable upon heating of said other leg by said heater element to engage said third contact member, and circuit means for said electric heater controlled by said first and second contact members.

25. An integrating relay apparatus comprising a substantially U-shaped member having substantially parallelly extending side elements and an integral base element joining said side elements, an armature pivotally secured to one of'said side elements adjacent one end thereof and adapted to pivot toward a position bridging the adjacent ends of said side elements, an electromagnet carried by said base element intermediate said side elements and operable when energized to pivot said armature toward its I armature and operable upon movement of said armature toward its bridging position to engage said first contact member, a second supporting member supported by one of said flange portions, a substantially U-shaped bimetallic element having substantially parallelly extending legs,

, means securing one end portion of one of said legs to said second supporting member, a third supporting member supported by the flange portion which supports said second supporting member, a third contact member carried by said third supporting member, an electric heater element adaptedtoheat the other of said. legs, a fourth contact member carriedby said other leg and operable upon heating ofsaid other legby said heaterelement to engage said third contact member, ,and circuitrneans for said electric heater conirolled by said first and second contact members.

References Cited in the file of this patent UNITED STATES PATENTS Appelberg '1, 1929 Smulski Oct. 25, 1932 Smulski Feb. 5, 1935 LaFierre Oct. 17, 1939 Werner Feb. 13, 194% Boucher Aug, 22, 1944 Nazar Nov. 7, 1944 18 Eaton Sept. 25, 1945 Boddy Sept. 17, 1946 Holmes July 1, 1947 Lindsay Jan. 27, 1948 Osterheld Oct. 12, 1948 Hall Nov. 16, 1948 Tobias June 21, 1949 Gognaire Dec, 11, 1951 Connoliy July 29, 1952 FOREIGN PATENTS Great Britain Nov. 5, 1934 Great Britain Nov. 7, 1947 

